The invention relates to a belt webbing, more particularly for an automatic seat belt, inflatable at least in part, comprising a tubular fabric applied to at least one flat side (top and/or bottom side) defined by side edges, extending longitudinally to the belt webbing.
"Webbing" or "belt webbing", "belt" or "seat belt" as termed in the following is always intended to mean substantially the same thing, i.e. always involving materials or semi-finished products for use in the manufacture of seat belts and webbing, this applying in the same way too, to the terms "tube" or "fabric".
One such belt webbing is known from German Patent 20 08 048 in which the belt evident therefrom is configured as a tube comprising a stitched-in burst fold configured in such a way that it bursts due to the tensile forces exerted by the belt in a crash situation and the opening of a valve coupled thereto causes inflation of the tubular belt. As a result of this the belt located as a flattened tube prior to the accident and whose width corresponds to half the circumference of the inflated belt is abruptly inflated. Due to this it represents to advantage, as compared to the simple belt, an impact cushion. However, adequate protection of the vehicle passenger is not satisfactorily assured due to the insignificant extent of the inflated tubular belt. An increase in the circumference of the belt tube with an inflatable cushion arranged in a part of the belt around the belt, likewise stated in the cited document, is also of a disadvantage since the corresponding cushion is not necessarily located at the right position and thus fails to be available for its actual purpose.
Known from the international patent application PCT/US 95/10695 is an inflatable tubular restraint system. The seat belt system shown in this case consists of a lap belt and a shoulder belt, the lap belt consisting regionally of an inflatable balloon, the length of which is shortened during inflation thus having in addition to the cushioning function also a belt tensioning function. In this arrangement, however, although that midriff zone of the passenger is particularly protected, the shoulder and head zone--except for an additional restraint of the shoulders due to the tensioned belt--fails to be taken into account.